Treatment of crude oil



June 28, 1960 2,942,689

J. P. WALKER ETAL TREATMENT OF CRUDE OIL Filed April 25, 1958 2 Sheets-Sheet l STORAGE INVENTORS Jay A? Walker BY Clarence 0. Glasgo June 28, 1960 J. P. WALKER ErAL TREATMENT OF CRUDE on.

2 Sheets-sheaf; 2

Filed April 25, 1958 INVENTORS Jay P. Walker Y Clarence O. G/dsyaw Q25 'water. with the oil. :the crude oil to avoid the expense of transporting 1t any TREATMENT OF CRUDE 01L Jay Poisar Walker and Clarence 0. Glasgow, Tulsa, Okla,

assignors to National Tank Company, Tulsa, Okla, a .corporation of Nevada Filed Apr. 25, 1958, Ser. No. 730,942

Claims. (CL 183-2.7)

-The present invention relates to the treatment of crude petroleum. More particularly, it relates to method and :apparatus for treating crude petroleum and simultaneously removing therefrom certain light hydrocarbon cosntituents while retaining in the oil so denuded a major ;portion of the next higher boiling hydrocarbon constituent.

The crude petroleum of a well stream may contam This water may be free or a portion emulsified It is desirable to remove this water from distance and in order to bring the product to a saleable :state. One conventional procedure for treating the crude 50H comprises heating it to a temperature sufiicient to separate the liquid and gaseous phases and to further resolve the water and oilif water is present. of heat necessary to treat crude oil well streams causes "the vaporization of those hydrocarbons of the oil having thelighter molecular weights. It is desirable to return a greater proportion of a selected molecular weight range .of these vaporized hydrocarbons to a liquid phase for .sale.

The degree The range of hydrocarbon molecular weights desirable It is not practical to poses on the lease or pass them to a point of recovery in gaseous form.

The next heavier hydrocarbons are the butanes. Depending on the percentage of butanes in the'treated oil, the pressure above atmospheric required to maintain them in liquid form may vary from a few ounces to many pounds. The Reid Vapor Pressure of the oil will, of course, vary with change in butane percentage. Again, generally, it may be said that it is desirable to obtain a clean, denuded, oil which is stable at pressures close to atmospheric and at the highest possible gravity. If the lighter hydrocarbons, having a range of molecular weights extending into the butanes, depending on the proportion, are allowed to remain in the treated oil, they will vaporize from the oil in storage and drive off heavier hydrocarbons. This will both lower the gravity and amount of the saleable oil. On the other hand, gas flashed and evolved in the treating process will have many of these saleable, liquefiable, storageable ends retained therein. It is desirable to recover as much of this saleable product as possible. To make this removal with separate iractionating equipment at the well location is expensive. The present invention provides a system for controlling the absorbing of a greater proportion of the butanes, and any heav- United States Patent ier hydrocarbons, out of the gas which is flashed and/or evolved from the separating and treating processes, by use of the treated, or denuded, oil.

The present absorption system adds to the system in which the characteristics and components of the Well stream are used exclusively for the entire cycle of taking crude petroleum from the Well and delivering'a maximum of stable, saleable oil to storage. The Well stream is used to cool the denuded oil to increase its absorption capacity. Additionally, the well stream is used to condense valuable fractions from the vapors evolved from the treating zone. All uncondensed less valuable, or desirable, vapors may be passed to gasoline plants, or other points of use, or a portion may be used to supply the burner of the treating zone. Denuded oil produced from the heated zone is used, in heat exchange, to heat the well stream as it is brought into the system to initiate the treating process. Finally, the cooled, denuded oil is used to absorb the storageable, valuable, molecular weights of hydrocarbons from the vapors flashed and/or evolved. The well stream itself is thereby used, exclusively, to prepare itself into a marketable product.

It can now be seen that one of the main objects of the invention is the control of the hydrocarbon constituents of gas separated and/or evolved from the treating of crude petroleum by use of the absorption capaicty of the demulsified, or denuded, oil.

Another object is to employ only the portion of denuded oil necessary to absorb the greater proportion of a selected molecular weight range of hydrocarbons from the gas flashed and/ or evolved from the treating of crude petroleum.

Another object is to reduce the temperature of the portion of denuded oil used to absorb the hydrocarbons to increase its absorption capacity and to simultaneously raise the temperature of the well stream to initiate the treating process of the well stream.

Another object is to employ the characteristics and components or" the well stream itself to produce the maximum possible saleable, stable, liquid product from the crude petroleum of the well stream.

The present invention contemplates provision of an absorbing tower wherein the denuded oil from the treater is used to contact the gaseous fractions separated and/or evolved from the treater in order to absorb from this gas the greater proportion of a selected molecular weight range of hydrocarbon constituents. The amount of denuded oil used for this absorbing process is controlled in order to use only that amount required to keep to a v predetermined minimum the selected molecular weight range of hydrocarbons'in the total gaseous output from the tower.

In another aspect the invention'contemplates division of a part of the gaseous fractions, flashed from the well stream in a separation step through an absorbing tower. Denuded oil from a treater is then routed in controlled portions through the tower to absorb a greater proportion of the hydrocarbons of a selected molecular weight range from the gas. All gaseous fractions evolvedin the treating step are routed through the tower. The portion of the flashed gas which is not diverted through the tower is combined with the total output of the tower to form a total gaseous product having a predetermined composition of hydrocarbons.

Another aspect of the invention contemplates the combination of an absorbing tower and treater with a heat ex- 7 denuded oil from the treater which is directed through the heat exchanger'and tower is controlled by an element V to the accompanying drawings in'whichz a-source; of treating heat. Any

7 V of'thegas' evolved beneath hood 12'is passed u pwardly byfconduit13."Oiland foreign'matter, se rat d t 7 of'theseparato r to condense valuable hydrocarbon vapors thereonevolving,fiorri'the treaten' Denuded absorbing oil from the treater is utilized-to heat the well stream in the exchanger; "'A'p'ortion of the l'elssvaluable vapors flashed in the separator are burned as a' source of heat for the treating section; lf'The process .is completed by intimately associating the denuded oil and vapors flashed t and evolved to abisorbifrom the'vapors a predetermined 7 portion ofvaluable'fractionsf" f The invention is more specificallydescribed by reference Fig. l is a somewhat diagrammatic illustration of a treating-absorbing apparatus combination: as one embodimentof the'inventionr f w 7 Fig. 2' is a diagrammatic illustration of. a control system for the regulating valves of the apparatus of Fig. '1. "Fig. 3is a sectioned elevation of a regulating valve used'to divide fluidfiow in the apparatus of Fig. 1.

{Figs 1, diagrammatically, illustrates acomplete system inwhichthe present invention is embodied. The. fluid circuit of "this system istr'aced from conduit 1, which brings-the wellstream of crude petroleum into the system. The well streamtis passed through heat exchanger 2'. In heafexchanger 2 'the"well.str eam is'heate d to initiate the freeing of any water'thatmay be in the stream and breaking of any emulsion. At the same time gaseous fail to condense are passed upwardly through conduit 16. 1

Conduits 13 and L6 join in conduit 17 to pass evolved gas trom the treating zone. Gas fiash-separated from the Well, stream' in separator', is pass d ut mist extractor 'into conduit '18. Although not specifically illustrated, it is to be understood that a portion of the separated gas of conduit 18,,or the tail gas from thecomplete system,

fractions-are released as well as foarnf Con duit 3 then takes t w l s e from c n r 2 o se a a or se -v tion-4; "Aconventional diverfer plate 5 spreads the well stream, by tangential flow,rover' internal walls efseparator section 4. This initialsepar'ation can be accomplished by' any numberof well-known arrangements. The pressurev reduction, on the wellstream at' this point causes gaseous ffactions-to"flash from the well' stream. Itis-common a v to provide a mist extractor 6 through which the flashed gastpasses upwardly ,and a conduit 7 which passes the liquid-phases-downwardlyq 'Bottom' 7A of the separator section 4 cooled by thecontacfwith' theliquidphases. #Gonduit 7fTRI6SlJt conventional arrangements for passing the liquid phasesofjthe wellfstream downwardly. The conduit 7 "terminates in a' spreade'fZplat efQbeneath I W V a free water in the ;well' stream passing down conduit :7 falls to the bottom of -thetreater-shell andjis drawn o'fijthi'oughi'conduit 10. The balanceof the liquids of'th well -streain isspread by 9 in order to denude the. stream of foreign matter and may be used to supply the burner of firetube 11 to heat the treating zone. r I

Invention is embodied in the process and apparatus in which these liquid and vapor phases are handled in going to, and coming from, treater 8. t The :well stream, and its components, is used to produce the ultimate product, which is merchantable oil in the largestquantity of the highest gravity possible from the particular well stream. An important element in this complete use oif the' well stream is absorption tower 20.

Absorption tower 20 is used to intimately contactithe gaseous phases from treater 8 with denuded oil taken therefrom in order for the denuded oil to absorb valuableifraetions'of hydrocarbons from the gas. Iris desired to operate this tower so the greater proportion of a selected molecular weight range of hydrocarbons, removed from the gas andabsorbedintotheliquid phase of the denuded oil may be storedat economic pressures, raising'the gravity and volume of the marketableioil;

Thephysical construction of vabsorbing tower20 may take any form which will intimately contact liquid-and gaseous phases. As illustrated, it consists essentially of a shell with trays 21 passing liquid from the top ofthe shell to the bottom and bubble caps22 which provide for gas to 'passtup the shell, and through the, liquid on trays 21' for intimate contact'with the liquid. v

The gasip'assed up shell 20 is'broughjt to the shell through conduit 23, under'the lowermost of thetrays 21.

After contacting the liquid, on. trays 21 intimately, throughbubble capst22, the gassis passedt'irom'thetop of shell 20 through conduit'24. t

The liquid on trays 21 through which the gas is passed 7 by means of bubble caps 22, is broughtin on the topmost of the trays 21 by conduit 25, passed down'the'successive trays 2 1 and removed from the bottom of thetower 20 by conduit 25A; Thus'is provided an'intimate, counter! current flow or the liquid and gaseous 'plias'esgthrough.

the volatile gases as the streaniisfiowed" and around firetu'bell 1 7 M V V .t rA hobdlZ is usually provided above firet'uhe 11. -Hood- 1z retains'the' liquids above firetube 11setheytwill receive maximum heating and more completely evolvefgases of both stableja'ndunstable characteristics. The result is their tobeing withdrawn asdenuded, a; cleanjoil.

column 20 which results in the liquid oil denudingthe gas of all but a smaller proportion of the heavier, selected 'molecular'weight, hydrocarbons; p V

Ihe objects of the invention are more, fully developed a by'appreciating this function-of absorption c0lu1nn'120fin [combination with treater v8 Using this structure'as a means for. the denuded oil from the treater to denude the gasof the treater resultsjin removing from the gas a a -high degree ofagitation ofthe lighter rising fluidsfon by t heheafof firetube 11," in "accordance i with their specific'gravities; 'Waftfenf'and any other foreign ma er, will'be drawnout at the ,trfeaterithrough outlet 1 rag d-105 with previously precipitated free water. i

denud d Oil is skimmed by we'ir, a d is pump nay be desirableto prevent the system from 'fi dgreater-proportion of its heavier hydrocarbon 'eonstitue fits. 'The'gas flashedinthe separating section 4 and that evolved into conduit '17 may all be passed, through -tovver 29 to deliver to conduit 26-a total gaseous product tram 'thesystem which contains only afsniall 'propdrtion of the; hydrocarbons of the lighter molecular weights which :willnoti remain in 'a liquid phase under CCOIlOIlllC pressures and normal ambienttl'temperature. It. is also" appreciated that in ,view of some particular conditions under which this combinationl'of absorptionitcolumn and absorption column 20. 75, llt i ls q t mpla g treater are operated, that; it, maybe desirable 'to'. leave a selectedportion of the heavier; hydrocarbon fconstituents in'the itotal product gas of conduit 26; 7 Therefore, con- 7 trol is provided over 'the preportion'of gas sent thron ismay e es a ta;

adjust the quantity of denuded oil placed in the upper portion of tower 26 for denuding the gas which is passed through tower 20. Therefore, control is exerted to proportion the denuded oil from conduit 15 between conduit 28 to tower 20 and conduit 27 to storage. A control system automatically analyzes the gaseous product from column 20 and adjusts the quantity of denuded oil from conduit 15 into conduit 25 which will maintain the output of the tower to a composition which includes a predetermined minimum of the selected heavier molecular weight hydrocarbons taken to tower 20 through conduit 23.

Another important element of the combination is heat exchanger 2. As shown, and previously indicated, the well stream of conduit 1 is passed through the tube side of heat exchanger 2 and into conduit 3. Additionally, that portion of the total denuded oil from treater 8, in conduit 15, which is split ofif, into conduit 25, is taken by conduit 28 into the shell side of heat exchanger 2 and delivered to conduit 25.

Heat exchanger 2 accomplishes at least two purposes. First, the well stream is given an initial heating before reaching the separation chamber 4. This initial heating is actually the beginning of the treating process. Heat introduced at this point starts evolving gas and precipitating water that may be in the stream. The result is that the separation in chamber 4 is helped by this preparation in its function of resolving the gaseous and liquid phases of the well stream, and the two parts of the liquid phase, traveling down conduit 7, are started toward a more complete separation. Second, the denuded oil from the treating zone is cooled to increase its absorbing capacity. In the treating zone the denuded oil and evolved vapors are near equilibrium. Cooling the denuded oil in exchanger 2 increases the ability of the oil to absorb the hydrocarbons in the gas with molecular weights falling within the selected range.

Regulation of the proportion of the conduit 15 denuded oil split between storage conduit 27 and conduit 28 of exchanger 2 is accomplished with valve 30. The valve element within the body of this valve splits the flow through conduit 15 in a proportion established by its position within a range of positions. The valve element is urged in one direction by a spring and is moved in the other direction by a diaphragm. The control fluid pressure placed on the diaphragm is developed by the control system which analyzes the gaseous product out of tower 20. If the analysis shows a deviation from the desired hydrocarbon content out of the tower, valve 30 is positioned to adjust the amount of denuded oil taken to the tower as an absorbing medium to returnthe gaseous output of the tower to its desired hydrocarbon content.

The control system analyzing the gaseous product from tower 20 is illustrated, in Fig. 1 as comprising a probe 31 which develops an electrical signal. Probe 31 is incorporated, as an element, of an electric network within instrument 32. The circuit of instrument 32 controls the rotation of motor 33 whose motion is used to control a mechanical fluid pressure transducing device 34. The fluid pressure output of 34 is imposed upon the diaphragm of valve 30 to position it until the flow through conduits 28 and 25 is adjusted to return the analysis of the gaseous product, made by probe, 31, to its desired value.

To exert control over that proportion of separated gas in conduit 18 combined with the evolved gas of conduit 17, valve 35 is connected to join conduits 18, 23 and 26. Depending on the position of the valve element of 35, the fluid flowing through conduit 18 is divided by valve 35.

Valve 35 is positioned by a control system continuously analyzing the product of conduit 26. It is first determined What proportion of the heavier hydrocarbons it is desired to pass into conduit 26. Valve 35 is adjusted to divide off the necessary portion of separated gas in conduit 18 which it is necessary to denude in the tower 7 20 to maintain this predetermined minimum of hydrocarbons of the selected molecular weight range. Probe 31A then actuates the electric network of instrument 32A to control the rotation of motor 33A. Motor 33A in turn controls transducer 34A to develop a fluid pressure to actuate valve 35 in proportioning the flow of conduit 18 between 23 and 26.

Referring to Fig. 2, there is shown a schematic illustration of a representative of the control circuits which make an analysis of the gaseous phases in Fig. 1 and controls the valves to reduce any deviation of the analysis from their set-point values. The control system for valve 30 is specifically considered as representative of both systems;

The probe 31 is shown in more detail than in Fig. 1 in order to make it clear that, as a condenser, it is comprised, essentially, of electrode 50 and sheath 51. Leads 52 and 53 include the condenser-probe 31 in the circuit 32. The circuit 32 develops a control signal for motor 33. Motor 33 is mechanically connected to mechanicalfluid pressure transducer 34 in order that a fluid pressure will be developed in conduit 54 for the diaphragm of valve 30. r

This general, and specific, arrangement is disclosed in Gunst et al. 2,720,624. As explained in that patent, it is known that hydrocarbons of different molecular weights have distinguishing dielectric constants. Although it has been customary in making dielectric-constant measure ments to pass the material to be tested through an electrical condenser whose electrical capacity is measured in a bridge circuit, this circuit disclosed by Gunst et al. overcomes errors of measurement, the sensitivity to capacity changes, frequency changes, etc. The disclosed circuit employs an electric condenser connected in a crystaloscillator circuit of a kind which undergoes a large step in the D.-C. plate current of its vacuum tube. The large step effects operation of relays which may be employed for actuating an indicator, alarm, recorder, controller or any other desired exhibiting means.

Similar to the circuit in the Gunst patent, the circuit of 32 has an oscillator tube 54. A quartz crystal 55 .is connected in its grid circuit, and it has a tuned plate circuit comprising the condenser formed by 50, 51, connected through adjustable transformer 56. The grid circuit also contains grid resistor 57 connected in parallel with crystal 55. A by-pass condenser 58 is connected between the tuned plate circuit and the cathode.

A controlled circuit is formed of the two relay coils 59 and 60, in series, and two A.-C. sources 59A and 60A, in series. This circuit is fed its input from the tuned plate circuit. An adjustable resistance 60B is included in the loop circuit of coils 59, 60 and sources 50A, 60A as well as the tuned plate circuit.

Relay coils 59 and 60 are polarized. Therefore, alternately increasing and decreasing voltage across them, arranged in series as they are, will cause them to operate in opposite directions. The alternate voltage change comes from the directional detuning of the oscillator circuit. Detuning of the oscillator circuit occurs when there is a change of the dielectric constant to which probe 31 is responsive. Variation of the predetermined proportion of hydrocarbons of a selected molecular weight range in the gas from tower 20 from its predetermined value gives such dielectric constant change.

The armatures 61 and 62 of relays 59 and 6d are normally closed with their contacts 63, 64. Armature-contact sets 61, 63 and 62, 64 are alternately completed to throw the line supply on either motor winding 65 or motor winding 66. Capacitor 67 is arranged to place the field of the windings out of phase from each other so the motor will rotate in one direction when the line supply is applied to Winding 65 and in the other direction when the line supply is applied to winding 66. When both relay windings 59 and 60 are energized both contacts are closed and the motor does not move because both na t andm t cd- 1 i7 7 motor windings a re energizedfrom the lineand are dynamically locking the motor. 7 Y 7 V Theacircuito 'nstrumen't 32is characterized in that it is operatedwvith a high'value of grid-resistance;iwhereby oscillations are maintained for small values of plate' cir'cuit n capacity. 'A'idiscontinuity or step place in the tube D .-C. plate current when theplate-tunedlcrystal oscillator goes onto, 'or ou't of, oscillation as {la-result of a change in the tuning of'theplat'e circuit, the latter being accomplished -by vary ing either'the capacityof 'probe 31 or the inductance 'of conpling'transformer 56. :Ava'riable capacitor 70"isv placed in parallel with probe 31, across 7 leads 52, 53; Adjustment of this capacitance will return Fig. 3 illustrates the structure of valves 30 -andj35;

Valve 30 is specifically considered as represent'ative of both valves. Valve 30 is shown as functioning in Fig. 1,"positioned toestabli'sh the proportiono'f conduit '15 how sent through conduit 28, returned through conduit 25a andcombined Withflow through conduit 27.

, Ther'sontrolffiuid pressure developed by transducer-34' and carried in line 75'is shownas impos'edflon the undera side of diaphragm 80.7 Theforce on diaphragm vsll is fopposed by the force ofs pring'i81. Ara'ng'e of-valvesfr the fiuid pressure of line, 751results i i-the movement of diaphragm -80, and attached valve stem 82, j through a range of positions; o K i t flow-splitting element 83 inthefform-of a -be'veled disc 'is fixed=totheend-0f stem 8 2. The disc 83 isfsized to a sliding fit in'the bore of the-bodyiand its range of positions spans openingsfrom conduit 1 into the body bore. By being so positioned,'element 83 splits the'ecnduit flow under the command of the eontrol fluid pressure ofjline 75, resulting in the sending of suificient amounts ofidenuded oil to tower: 20 to maintain the gas product-cf conduit 24 at its predetermined value,

From theforegoingit will'beseen that this invention is'on'e W611 adapted to attain "all of the. ends and objects re ab v et f rth; c the g hb e a an which are obvious ap'd f which flare :inherent to K the apj .It willjbe understoodfthat certainifea tures sube .As many possible embodiments'may bemade fof the-in:

vention without departing: from the scope" thereof, it is to passesiinto the structu re in accordance-with the analysis a i so combinationsareof utility'andjmay be employed without referenceto fother'features jand subcornbin'ations. *{Ilhjs is,

be understood that all ,matter herein set forthor shown 7 in the accompanying drawings is tob'e interpreted as illustrative and notjin a limitin'g sense. a a

T FIhe'invention having been described, what is claimed is:

A method of treating c'rudepetroleuin an'dits gases and retaining the recovered ,oil a major proportion of hydrocarbonsiof a "selected molecular weight range, which 7 feeding a portion of the denuded oil into structure which brings the oil 'intotintimatercontactw-ith vapor, passing into the contacting structure fat, least 'a portion of fthe evolved gaseous 'fr'action'sfor intimate contactIwith ,the oil, continuously analyzing, the gas from-the contacting structure to detect the presence ofhydrocarbons j'df a selected range. of molecular weights, constantly and 'autoi V fi lly ,ut i s' the ana i i o t l he; i e. Offt i portion'ofthe denudedpihfed into the contacting*"struc-' stable liquid, which compriseapassing crude petroleum into a separating'zone wherein hydrocarbon gas in the crude'isfiashed and removed, passing the crude into a heatingzone and heating it to resolveits'liquidphases including denuded oil; and hydrocarbon gaseous fractions, feeding -a -porticn of the denuded oil 1 into a structure for intimatecontact'with gas, passing combined portions of the flash-separatedand evolved hydrocarbon gaseous fractions into the contacting structure for intimate contact with the denuded oil, continuously analyzing the gas from the contacting structure for its constituent of hydrocarhe rs of storable molecular weight, continuously and automatically utilizing the analysis to control the quantity of the denuded oil'fed to the contacting structure in order totabsorb from the combined 'portions'of the flash-separated and evolved hydrocarbon 'gaseous'fractions a desired naxirnum of storable hydrocarbons, withdrawingthe nuded oil gis'fed tofthe contacting structure and before a the crude is passcdinto the separating zone so that' the denuded'oil portion will be cooled to increase its absorbing capacity and the crude will be heated toin'itiate the treating process. Y

'4. The :rnethodof claim 12 including,- combining'the denuded gas-from the structure outlet with the remaining portion of the separated gas into a total gas, continuouslyanalyzing the/combiner} total gas from the process as to its proportion of hydrocarbons of storable molecular weight, and controlling the siz'erof the separated gas portion 'whichiiscombined with evolved gas and of the totalfgas 'toproduce atotalgas product witha *5. An apparatus for treating crude petroleum and refa-ining a major proportion of the hydrocarbonsof a a selected molecular weight range in'the denuded. oil pro duced' including, aftreater having a 'heatingizoneinto V which the'crude'stream isconducted, means for su pplyingvheat to the heating zone, firsttregulating means for splitting ofia'portion -of the denuded oil from ithe aone, 7

an;absorbing towerfor bringing liquid and gases "in, intimate contact, meansfor conducting the split-ofiportion ctzthe'denuded oil to the tower, fmeans for'rco'nducting at'least a portion of the" separated and evolved fgases from the trefater to the, tower for intitnatejcontact with the denudedroil portion, so, that the total gas portion will 7 have absorbed from it the'majof proportiont of hydromeans continuously and automatically modulated 'bythe analyzer to position the first regulating means'in splitting elf-the. portion of denuded'ofl for the tower which will absorb a predetermined portion 'e'fthe hydrocarbons of selectedmolecularweight i redetermined proportion 'of hydroeairbons of storable vmolecular-weight. i

a a a t 'eifi mlt t fol-taking the 'saturated oil'tostorager Q a the total gas output of the apparatus, a second analyzer responsive to the total gas output in order to detect the proportion of hydrocarbons of selected molecular weight range in the total gas, and a second control means responsive to the second analyzer for positioning the second regulating means which will maintain the total gas output with a predetermined proportion of the hydrocarbons of selected molecular weight range.

8. A method of using a well stream of crude petroleum to produce the maximum amount of stable, saleable oil including heating the well stream to initiate the process of its treating, separating liquid and gaseous phases of the well stream, forming a source of heat from at least a portion of the flashed gaseous phase, heating the liquids with the heat source to resolve them into their component parts and to evolve hydrocarbon gas, condensing a portion of the liquefiable' hydrocarbons'from the gas by the well stream in the separation step, cooling oil denuded of the hydrocarbon gas by heating the well stream to initiate the treating process, contacting at least a portion of the gas with the cooled denuded oil to absorb stable and saleable hydrocarbons therefrom which are liquefiable at substantially ambient conditions, continuously analyzing the gas portion after it contacts the cooled denuded oil to detect its residual content of stable and saleable hydrocarbons which are liquefiable' at substantially ambient conditions, and continuously and automatically controlling the amount of cooled oil contacting the gas in accordance with the analysis.

9. A method for treating a petroleum well stream containing gas and liquids to produce a stable product of predetermined storable Reid Vapor Pressure, which comprises, fiashing gas from the well stream at a first temperature, passing the remaining liquid of the well stream into a zone in which heat is applied at a second temperature to the well stream to drive oflf light volatile ends of hydrocarbons from the Well stream, collecting the gas driven from the well stream at the second temperature, withdrawing oil denuded of light volatile gas from the heated zone, passing the oil from the heated zone and passing the well stream to the flashing zone in heat exchange relationship to each other to cool the denuded oil and heat the well stream, passing the cooled denuded oil in counter-current flow with the collected gas to absorb hydrocarbons from the gas by the oil which will not raise the vapor pressure of the oil and absorbed hydrocarbons above a predetermined storable vapor pressure, continuously analyzing the denuded gas passed in countercurrent flow with the cooled denuded oil to detect its content of those hydrocarbons which will not raise the vapor pressure of the oil above the predetermined vapor pressure, continuously and automatically controlling the quantity of the cool denuded oil portion passed in countercurrent flow with the gas in accordance with the analysis, and passing the stable absorbing oil to storage and the denuded gas to a point of recovery and use.

10. A method of treating crude petroleum and its gases and retaining in the recovered oil a major proportion of hydrocarbons of a selected molecular weight range, which comprises, passing crude petroleum into a treating zone, heating the crude in the zone to resolve its gaseous and liquid phases including denuded oil and to evolve desirable and undesirable hydrocarbon gaseous fractions, cooling a portion of the denuded oil with the crude petroleum passing into the treating zone, feeding the cooled portion of the denuded oil into structure which brings the cooled oil into intimate contact with vapor, passing into the struc ture at least a portion of the evolved gaseous fractions for intimate contacts with the cooled oil, continuously analyzing the gas from the contacting structure to detect the presence of hydrocarbons of a selected range 'of molecular weights, controlling the size of the portion of the denuded oil cooled by the crude petroleum and fed into the structure so the gas will have absorbed from it a predetermined maximum proportion of hydrocarbons of a selected range of molecular weights as established by the analysis, withdrawing the denuded gas from the contacting structure, and withdrawing the cooled oil portion from the contacting structure after it has absorbed a major portion of the hydrocarbons or theselected range of molecular weights.

11. A method of treating crude petroleum and retaining in the recovered oil a greater portion of the hydrocar bons of molecular weights which are storable and saleable as stable liquid, which comprises, passing crude petroleum into a separating zone wherein hydrocarbon gas in the crude is flashed and removed, passing the crude into a heating zone and heating it to resolve its liquid phases including denuded oil and hydrocarbon gaseous fractions, cooling a portion of the denuded oil with the crude petroleum passing into the separating zone, feeding the cooled portion of the denuded oil into a structure for intimate contact with gas, passing combined portions of the flashseparated and evolved hydrocarbon gaseous fractions into the structure for intimate contact with the cooled denuded oil, continuously analysing the gas from the contacting structure for its constituent of hydrocarbons of storable molecular weight, controlling the quantity of the denuded oil cooled by the crude petroleum and fed to the contacting structure in accordance with the analysis in order to absorb from the gas a desired maximum of storable hydrocarbons, withdrawing the denuded gas from the structure, and withdrawing the cooled oil portion from the structure after it has absorbed the larger proportion of the storable hydrocarbons.

12. An apparatus for treating crude petroleum and retaining a major proportion of the hydrocarbons of a selected molecular weight range in the denuded oil produced including, a treater having a heating zone into which the crude stream is conducted, means for supplying heat to the heating zone, first regulating means for splitting off a portion of the denuded oil from the zone, an absorbing tower for bringing liquid and gases in intimate contact, a heat exchanger receiving the crude stream and the split-01'1" portion of the denuded oil from the heating zone, means for conducting the cooled split-off por tion of the denuded oil to the tower, means for conducting at least a portion of the separated and evolved gases from the treater to the tower for intimate contact with the cooled denuded oil portion so the total gas portion will have absorbed from it the major proportion of hydrocarbons of selected molecular weights, an analyzer responsive to the denuded gas portion flowing out of the tower in order to detect the proportion of hydrocarbons of the selected molecular weight range which have not been absorbed from the gas, control means responsive to the analyzer to position the first regulating means in splitting ofi the portion of denuded oil for the tower which will absorb a predetermined portion of the hydrocarbons of selected molecular weight range from the gas, and means I for taking the saturated oil to storage.

13. The apparatus of claim 12 including, second regulating means for determining the quantity of the total gas from the treater conducted to the tower to be denuded by the cooled denuded oil portion, means for combining the denuded gas from the tower with remaining gas from the treater to form the total gas output of the apparatus, a second analyzer responsive to the total gas output in order to detect the proportion of hydrocarbons of selectedzmolecular weightrange, in.the:tota1v gas, a'nd?a second :control means responsive to the second analyzer: for. positioning the. second regulatingmeans' which willv maintain the total gas output with a predetermined pro portion of the hydrocarbons of selected molecular. weight:

range. a l

14; A- method of using .a well streamjoi crude petro tleum to produce the maximum amount of stable,isaleable oil including; heating the. well stream to initiatethe process of its, treating, separating; liquida'aud' gaseous phases of thewell stream, forming a source vof heat from at. least a'portion of theflashed gaseous'phase; heating theliquids with the heat source to resolge'them'intortheir component pa'rtsand to evolvehydrocarbon gas, conrdensing a portion of the.liquefiablerhydrocarbons-fromthe gas by theswell stream in the separation step, coolinga portion'of the oil denuded of the hydrocarbongas by heating the well stream to initiate theitr'eating process,

contacting at least a portion of the gas with the portion of cooled denuded oil to absorb stable and saleable hydrocarbons therefrorn, and controlling the amount of the portion of cooled denuded oil contacting the gas in ac-' cordance with an analysis of the gas after it has had the" hydrocarbons absorbed therefrom.

15. A method 'for'treating a petroleum well stream 25" containing gas and liquids to produce astable product of predetermined storable Reid VaporPressure, which com+ '12 a prises; flashing 1 gas from the well stream at :a first temperature, passing the--remaining liquid-of the well stream intoa-zone in whichheat is applied at a second temperature tothewell streamto drive ofilight volatile ends of hydrocarbons from the well stream, collecting the gas drivenafrom the well stream at the second temperature,

withdrawing oil denuded of light volatilegas from the heated zone, passing a portion of the oil from the heated zone and passing :the well stream to the flashing zone in. 'heat exchange relationship to each other to cool the de-' nuded oil portion andhea'tthe well stream, passing the portion of the cooled denudedoil' in counter-current flow .with the collected gas to absorb hydrocarbons from the gas by the oil which will not raise the vapor pressure of the oil and absorbed hydrocrabons above a predeter. minedstorable vapor pressure, controlling the quantity of 'theucool denuded oil port-ion in accordance with the 2,420,115 Walker et a1, V May 6, 1947' 2,720,624 Gunst et a1. Oct. 11, 1955, 27K14 Mmae 

